if errCode != ErrNone {
		return cred, "", "", time.Time{}, errCode
	}

	// Verify if region is valid.
	region = signV4Values.Credential.scope.region

	// Extract date, if not present throw error.
	var dateStr string
	if dateStr = req.Header.Get("x-amz-date"); dateStr == "" {
		if dateStr = r.Header.Get("Date"); dateStr == "" {
			return cred, "", "", time.Time{}, ErrMissingDateHeader
		}
	}